Detergent Washing Research Articles

A novel method to determine residual detergent in biological samples post endotoxin reduction treatment and evaluation of strategies for subsequent detergent removal

Endotoxin removal using detergent washes and extractions are well-established, efficient, and cost-effective methods; however, removing residual detergent post treatment has been shown to be a challenge. In this communication, we show a simple and fast method for determining the detergent concentration in a protein solution post treatment and highlight strategies for detergent removal to achieve levels below the critical micelle concentration (CMC), the minimum concentration at which detergent micelles form.

Ultrasensitive and highly selective graphene-based single yarn for use in wearable gas sensor.

Electric components based on fibers or textiles have been investigated owing to their potential applications in wearable devices. High performance on response to gas, drape-ability and washing durability are of important for gas sensors based on fiber substrates. In this report, we demonstrate the bendable and washable electronic textile (e-textile) gas sensors composed of reduced graphene oxides (RGOs) using commercially available yarn and molecular glue through an electrostatic self-assembly. The e-textile gas sensor possesses chemical durability to several detergent washing treatments and mechanical stability under 1,000 bending tests at an extreme bending radius of 1 mm as well as a high response to NO2 gas at room temperature with selectivity to other gases such as acetone, ethanol, ethylene, and CO2.

Graded metal carbon protein binding films prepared by hybrid cathodic arc — Glow discharge plasma assisted chemical vapor deposition

Graded composite layers containing metal and plasma polymer components were deposited using a cathodic arc in conjunction with plasma immersion ion implantation. Using a bias potential throughout, pure metal was deposited initially using the cathodic arc alone and then acetylene was added to the process to increase the fraction of the plasma polymerized carbon film. To test adhesion, the substrate and film were strongly deformed by folding the substrate inward and outward with a small radius of curvature. Strong adhesion between the metal surface and the deposited layers was achieved by the use of the graded layers as inferred from the SEM observations of the deformation region. Strong adhesion of biologically active protein molecules to the surface of the graded layer was confirmed by detergent washing and colorimetric enzyme activity assays. These characteristics suggest that the coatings may be suitable for cardiovascular stent applications.

Effects of washing, peeling, storage, and fermentation on residue contents of carbaryl and mancozeb in cucumbers grown in greenhouses.

Cucumbers grown in two different greenhouses were exposed to mancozeb and carbaryl at different times. The effects of 10-day preharvest period, water and detergent washing, peeling, predetermined storage period at 4°C (refrigeration), and fermentation on the reduction of residue levels in the plant tissues were investigated. Mancozeb and carbaryl residues in cucumbers were determined by gas chromatography-electron capture detection. Results showed that residue levels in samples, which were collected after 10 days following the pesticide application, were significantly lower than the samples collected after 2 h subsequent to the pesticide application. The culinary applications were effective in reducing the residue levels of the pesticides in cucumbers. As a result, non-fermentative pickling in sodium chloride and acetic acid was the most effective way to reduce the mancozeb and carbaryl residues of the cucumbers.

Identification properties of a recombinant class I hydrophobin rHGFI

Hydrophobins fulfill various functions in fungal growth and morphology. These proteins can self-assemble at hydrophilic/hydrophobic interfaces and form amphipathic membranes. Based on their physical properties and hydropathy patterns, hydrophobins are divided into two classes (I and II).In order to identify the recombinant class I hydrophobin rHGFI, the different properties between rHGFI and the typical class II hydrophobin rHFBI were investigated. In contrast to rHGFI, no rodlet structure was observed on rHFBI coated mica surface, and the membranes formed on siliconized glass surfaces by rHFBI were not robust enough to resist treatment with 60% ethanol and 2% hot SDS. In contrast, the membranes formed by rHGFI on siliconized glass surfaces were so strong that could resist hot detergent and alcohol solution washing. Moreover, self-assembly of rHFBI at the water–air interface was not accompanied by a change in secondary structure. Meanwhile, β-sheet structures dramatically increased after rHGFI self-assembled at water–air interface, which could cause the fluorescence intensity of Thioflavin T increased and Congo Red and CD absorption spectra shift. Water-insoluble erythrosin B dispersion prepared with rHGFI and rHFBI were both stable for more than one month, which indicated that the interaction between erythrosin B and rHGFI/rHFBI was strong. This might promote rHGFI and rHFBI to be considered as potential dispersing agents to stabilize water-insoluble erythrosin B.

Phase segregation of polymerizable lipids to construct filters for separating lipid-membrane-embedded species.

Supported lipid bilayer (SLB) platforms have been developed to transport and separate membrane-embedded species in the species' native bilayer environment. In this study, we used the phase segregation phenomenon of lipid mixtures containing a polymerizable diacetylene phospholipid, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DiynePC), and a nonpolymerizable phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), to create filter barrier structures in SLBs. Upon exposing the phase segregated samples to UV light, the DiynePC-rich domains could become crosslinked and remain fixed on the surface of the support, while the DOPC-rich regions, where no crosslinking could happen, could be removed later by detergent washing, and thus became the void regions in the filter. During the filter fabrication process, we used the laminar flow configuration in a microfluidic channel to control the spatial locations of the feed region and filter region in the SLB. The flow in a microfluidic channel was also used to apply a strong hydrodynamic shear stress to the SLB to transport the membrane-embedded species from the feed region to the filter region. We varied the DiynePC/DOPC molar ratio from 60/40 to 80/20 to adjust the cutoff size of the filter barriers and used two model membrane-embedded species of different sizes to examine the filtering capability. One of the model species, Texas Red 1,2-dihexa-decanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (Texas Red DHPE), had a single-lipid size, and the other species, cholera toxin subunit B-GM1 complex, had a multilipid size. When the DiynePC/DOPC molar ratio was 60/40, both species had high penetration ratios in the filter region. However, when the ratio was increased to 70/30, only the Texas Red DHPE, which was the smaller of the two model species, could penetrate the filter to a considerable extent. When the ratio was increased to 80/20, neither of the model species could penetrate the filter region. The results showed the possibility of using phase segregation of a mixture containing a polymerizable lipid and a nonpolymerizable lipid to fabricate filter barrier structures with tunable cutoff sizes in SLBs.

Infection Control Measures in Some Selected Private Dental Clinics of Dhaka City

Infection is one of the most vital problems in health care service worldwide. A cross-sectional study was conducted to assess the standard and level of current infection control practice in the Dental clinics in Dhaka city. A total 110 purposively selected respondents participated in this study, most of them were from middle age group. Among them 68% were male and 32% were female. 62% respondents had graduate level education. By length of practice duration 53.6% had 5-10 years experience and 30.0% treat average 5-10 patients daily. Among the total respondents 77% of Dental surgeons were vaccinated against tetanus and hepatitis and 56% of respondents used to wash hands by water with soap. Within the total participating dentists 66% gave the history of habitual wearing of disposable gloves, 70.0% used disposable masks and 26.4% wore disposable clothes. The study also reported that, 44% of respondents usually washed clinical contact surface in the dental operatory by disinfectants and 33% of respondents cleaned the operatory surfaces after patient's treatment by water and antiseptics. The study revealed that almost all dental surgeons used to use the disposable instruments & accessories in the clinic, 4I% clinicians used dettol in the clinic as disinfecting solution and 35.8% respondents sterilized their instruments by autoclave. The research work found that 73.6% respondents mentioned to clean the prosthodontic instruments by detergent wash, 68.2% mentioned to use glass bid sterilizer to sterilize the endodontic instruments and 68% reported about surgical instruments to sterilize by autoclave just after cleaning with detergent wash without using the disinfectant solutions. This study also found that 77.3% disposed the sharp instruments in plastic container, 20.9% maintained color code during disposal of medical wastes and 58.2% respondents used to dispose medical wastes with general wastes. The study revealed that 69.1% cleaned the non patient area by mop and detergent only. According to the agreements of the respondent's 71% reported that very few of the patients complained about secondary infection, 81% gave no history of cross infection after receiving operative procedure. 50.9% respondents mentioned about participation in training session on infection control procedure at least once in their lifetime. Policy on immunization should be developed for Dental health workers and farther studies involving larger sample size is recommended. DOI: http://dx.doi.org/10.3329/bjdre.v4i2.20252 Bangladesh Journal of Dental Research and Education Vol.4(2) 2014: 65-69

Optimizing Detergent Formulation with Enzymes

AbstractEnzymes have been widely used in modern detergents. However, few studies deal with research on enzyme dosage as well as its relationship with other ingredients within detergent products. This paper compares the washing performance of Chinese phosphate and non‐phosphate detergent before and after adding different enzymes and additives on the various types of swatches. The results confirmed that the detergent washing performance with enzymes added improved significantly for the specific stain soil. And within a certain range, the detergent washing performance and enzyme content have positive correlation. Furthermore there is synergy of soil removable ability between protease and amylase. Meanwhile the citric acid and various additives with enzymes can effectively compensate for insufficient of non‐phosphate detergent.

Residue Removal of Pesticides from Brinjal Using Different Processing Methods

The present study was conducted on the residual removal of six pesticides (bifenthrin, profenofos, endosulfan, imidacloprid difenthiuron and emamectin benzoate) from brinjal by using various house hold processing methods such as washing, detergent washing, peeling, drying and cooking/frying etc. The data revealed that high amount of all pesticide residues (above MRLs) were present and unfit for human consumption in raw form. From water soluble pesticides diafenthiuron reduced more in blanching as compared with imidacloprid and emamectin benzoate. Frying reduced the residues more effectively, rendering it fit for human consumption. Washing followed by frying reduced the fat soluble residues >70% whereas water soluble pesticide residues >80%. It was concluded that each processing was found to be effective in reduction of pesticides residues.

Enzymatic removal of burnt-on protein residues from solid surface: A potential food equipment cleanser

Burnt-on protein residues on the surfaces of the utensils used in dairy and meat processing industries possess a major challenge, where routine cleaning operations involve the use of hot alkali and/or acid, detergent washes followed by heat or chemical sanitization. These conventional cleaning approaches are neither economical nor eco-friendly. An economic enzymatic approach using alkaline protease isolated from Bacillus pseudofirmus strain SVB1 is envisaged. The efficiency of the alkaline protease (crude extract and partially purified enzyme) in removing burnt-on protein residues from solid surface was monitored by three-dimensional atomic force microscopy and protein quantification methods. In addition, the efficiency was also compared with that of the commercially available alkaline proteases. Crude alkaline protease obtained from SVB1 removed casein, dairy effluent, abattoir effluent and poultry effluents from the model solid surface efficiently. Results showed that the crude enzyme significantly removed casein when compared to the commercially available alkaline proteases. After this enzymatic cleaning and subsequent treatment, no residual enzyme activity was detected.

Ion implantation treatment of beads for covalent binding of molecules: Application to bioethanol production using thermophilic beta-glucosidase

We have achieved plasma immersion ion implantation (PIII) treatment of beads and powders using a specially designed plasma treatment system. This simple one-step production of functionalized beads provides an attractive alternative to current commercial functional beads, for which proteins must be chemically attached using linkers.Using the enzyme beta-glucosidase as an example we show that PIII treatment of polyethylene beads enables covalent binding with increased activity of the enzyme compared to the untreated beads. Covalent binding was confirmed using detergent washing. The covalently immobilized enzyme has a broader pH range over which it has high activity than the enzyme in solution. The stability of the immobilized molecules was examined using reaction rate as a function of temperature and was shown to be significantly higher on the PIII treated beads compared to untreated beads. We attribute the increased enzyme activity on PIII treated beads to increased protein binding density and better retention of conformation. The results of this work are of significance in the production of ethanol using a flow process. Covalent binding to beads allows more robust attachment for high flow rates, high activity, large surface area and a broad operating pH range. Treatment could be easily adapted for a range of applications such as linking drugs, dyes and proteins to particles of an appropriate size.

Hydrophobic adsorption and covalent immobilization of Candida antarctica lipase B on mixed-function-grafted silica gel supports for continuous-flow biotransformations

Adsorption onto solid supports has proven to be an easy and effective way to improve the mechanical and catalytic properties of lipases. Covalent binding of lipases onto the support surface enhances the active lifetime of the immobilized biocatalysts. Our study indicates that mesoporous silica gels grafted with various functions are ideal supports for both adsorptive and covalent binding for lipase B from Candida antarctica (CaLB). Adsorption of CaLB on phenyl-functionalized silica gels improved in particular its specific activity, whereas adsorption on aminoalkyl-modified silica gels enabling covalent binding with the proper reagents resulted in only moderate specific activity. In addition, adsorption on silica gels modified by mixtures of phenyl- and aminoalkyl silanes significantly increased the productivity of CaLB. Furthermore, CaLB adsorbed onto a phenyl/aminoalkyl-modified surface and then treated with glutardialdehyde (GDA) as cross-linking agent provided a biocatalyst of enhanced durability. Adsorbed and cross-linked CaLB was resistant to detergent washing that would otherwise physically deactivate adsorbed CaLB preparations. The catalytic properties of our best immobilized CaLB variants, including temperature-dependent behavior were compared between 0 and 70°C with those of two commercial CaLB biocatalysts in the continuous-flow kinetic resolutions of racemic 1-phenylethanol rac-1a and 1-phenylethanamine rac-1b.

세척방법에 따른 양파껍질추출물의 Quercetin수율 및 잔류농약 제거효과

This study was conducted to assess the removal of residual pesticides and to obtain high amounts of quercetin in onion peel extracts (OPEs) by 4 washing treatments. Washing is one of the standard processing steps in obtaining functional food ingredients from onion peel. After a first detergent wash (0.2% w/v) (DW) and hot air drying (80oC, 24 hr) (B), 4 washing treatments were tested, including a second DW (C), ultrasonication (50oC, 10 min) plus DW (D), 0.3% H2O2 (v/v) plus DW (E), and blanching (95-97oC, 2 min) plus DW (F). This was followed by 60% (v/v) ethanol extraction and vacuum freeze drying of the OPE. The E treatment yielded 89.04% OPE and a quercetin content of 96.84% in the OPE compared with the B treatment, and had the highest efficiency of all treatments tested. The OPE was tested for the presence of 177 residual pesticides and three compounds were detected in all treatments: cyhalothirn, fluquinconazole and procymidone. Cyhalothirn and fluquinconazole levels were below the permitted levels for fresh onion, while procymidone was present in the high level range of 128.01~133.46 mg/kg in all samples. The E treatment was a better washing method than the others for removal of residual pesticides. It could reduce the level of residual pesticides without changing the functional properties of the OPE.

An improved method for rapid quantitative analysis of the insoluble dietary fiber in common cereals and some sorts of beans

An improved rapid analysis for determining the content of insoluble dietary fiber (IDF) in common cereals and some sorts of beans is described in this paper. The procedure includes starch gelatinization in water bath for 20 min at 100 °C and 2.5% (w/w) α-amylase hydrolyzed reaction followed by neutral detergent wash and acetone extraction. Compared with 1.5 h for filtration (estimated) and 18 h for the enzymatic hydrolysis required by the typical American Association of Cereal Chemists (AACC) method, the filtration and enzymatic treatment procedures in the improved method was completed within 15 min and 1.5 h, respectively. The length of time for the filtration and the enzymatic hydrolysis for the improved method was significantly shortened from 19.5 h (AACC method) to 1.75 h. In addition, orthogonal array design (OAD) has been applied to optimize parameters of the improved method. The recovery yield of microcrystalline cellulose was 97.75% (w/w), in agreement with the result obtained using the typical AACC method, demonstrating the reliability of the improved method. Furthermore, several common cereals and beans were employed to validate the accuracy and universality of this improved method.

Electrodeposition of a Biopolymeric Hydrogel: Potential for One-Step Protein Electroaddressing

The electrodeposition of hydrogels provides a programmable means to assemble soft matter for various technological applications. We report an anodic method to deposit hydrogel films of the aminopolysaccharide chitosan. Evidence suggests the deposition mechanism involves the electrolysis of chloride to generate reactive chlorine species (e.g., HOCl) that partially oxidize chitosan to generate aldehydes that can couple covalently with amines (presumably through Schiff base linkages). Chitosan's anodic deposition is controllable spatially and temporally. Consistent with a covalent cross-linking mechanism, the deposited chitosan undergoes repeated swelling/deswelling in response to pH changes. Consistent with a covalent conjugation mechanism, proteins could be codeposited and retained within the chitosan film even after detergent washing. As a proof-of-concept, we electroaddressed glucose oxidase to a side-wall electrode of a microfabricated fluidic channel and demonstrated this enzyme could perform electrochemical biosensing functions. Thus, anodic chitosan deposition provides a reagentless, single-step method to electroaddress a stimuli-responsive and biofunctionalized hydrogel film.

Introducing Doolittle multivariate calibration algorithm for infrared spectrometric determination of STTP, SS, and SC in Iranian washing powder

The basic principle of Doolittle multivariate calibration algorithm (DMCA) was investigated and used for simultaneous quantitative determination of sodium tripolyphosphate (STPP), sodium sulfate (SS), and sodium carbonate (SC) in commercial washing powders with serious overlapping. The process of the Doolittle decomposition algorithm (DDA) is implemented by lower and upper (LU) triangular matrix decomposition which is robust and convenient. Then it was applied to overcome the problem of overlapping spectra of different components in the detergent washing powder. The root mean square error of prediction (RMSEP) for DMCA is 0.084 which confirms the improvement in accuracy, in comparison with K-Matrix (KM) (RMSEP=0.118). It was demonstrated that DDA can avoid matrix inverting, reduce the orders of matrices, and needs a little time for analysis. Therefore, it has bright prospects in chemometrics and it is feasible that the Doolittle algorithm could be applied to the practical determinations in real samples with spectral overlapping.

Fouling Mechanisms in Axial Compressors

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Fouling is caused by the adherence of particles to airfoils and annulus surfaces. Particles that cause fouling are typically smaller than 2 to 10 microns. Smoke, oil mists, carbon, and sea salts are common examples. Fouling can be controlled by appropriate air filtration systems, and can often be reversed to some degree by detergent washing of components. The adherence of particles is impacted by oil or water mists. The result is a build up of material that causes increased surface roughness and to some degree changes the shape of the airfoil (if the material build up forms thicker layers of deposits), with subsequent deterioration in performance. Fouling mechanisms are evaluated based on observed data, and a discussion on fouling susceptibility is provided. A particular emphasis will be on the capabilities of modern air filtration systems.

Effect of Household Processing on the Removal of Pesticide Residues in Okra Vegetable

The study has been designed to determine the extent of pesticide residues removal from okra through household processing. For this, okra crop was grown on university farm and application of pesticides were carried out at recommended dosage. After 24 hours, the okra was harvested, labeled and brought to the laboratory of Institute of Food Sciences and Technology, Sindh Agriculture University, Tandojam for their analyses and further processing such as washing, detergent washing, sun-drying and cooking, etc. being practiced at various households. Pesticide residues were extracted from okra by solvent partitioning and cleaned by C18 cartridges/activated charcoal by using acetonitrile for elution and then cleaned up residues were analyzed through HPLC-UV. The analysis of data revealed that imidacloprid is highly effective against pests at low dosages and its residues in processed as well as unprocessed okra samples were within MRLs (0.5ppm). Imidacloprid residues 0.31 ppm in unwashed okra was reduced to 0.082 ppm by detergent washing (73% removal). Emamectin benzoate residues were high in unwashed okra (0.51 ppm as against MRLs of 0.2ppm), however, its residues were reduced to MRLs by detergent washing and subsequent processing by frying, thermal dehydration or sun-drying of detergent washed okra.

Removal of Pesticide Residues from Okra Vegetable through Traditional Processing

Demand for vegetables in Pakistan is constantly increasing to feed growing population. Pakistan is the second largest producer of okra and in Sindh okra is produced throughout the year. Okra crop is attacked by variety of insect pests and commercial okra production relies heavily on the pesticides belonging to organochlorine, organophosphate, carbamate, pyrethroid and neo-nicotinoid groups for pest control. Moreover, growers do not observe safety interval for okra harvest. Hence the okra sold in Pakistani markets is highly contaminated with pesticide residues. Aim of this research study was to determine the extent of pesticide residue decontamination in okra vegetable through traditional processing. Okra crop was sprayed with bifenthrin, profenofos and endosulfan, and different processing were applied on okra such as washing, detergent washing, sun-drying and cooking, etc. Bifenthrin, profenofos and endosulfan pesticide residues were extracted from okra by solvent partitioning and cleaned up through Florisil column using organic solvents for elusion as described by EPA and FDA procedures. Cleaned up residues were analyzed through GC-µECD. The results revealed that endosulfan levels were reduced to MRL by detergent washing (from 2.01 ppm in unwashed samples to 1.03ppm). Profenofos residues (3.21ppm) were reduced to MRL (2.0ppm) by detergent washing and by combination of plain water washing and frying. Bifenthrin MRL is very low (0.04ppm) and only combination of detergent washing and frying reduced residues from 0.311 ppm to 0.042 ppm.

Effect of Surface Treatment on Betel Nut (Areca catechu) Fiber in Polypropylene Composite

Betel nut fiber (Bn)/polypropylene (PP) composites were prepared in the different ratio of 10:90, 20:80, 30:70, 40:60 (Bn wt%:PP wt%) using extruding and hot press moulding technique. From the results, it can be inferred that Bn30:PP70 mixture composite (BnPP) showed better performance among the composites prepared. For further improvement, betel nut fiber was subjected to detergent wash as well as alkali treatment for composite preparation. This work investigated the tensile strength, bending strength, tensile modulus, bending modulus, elongation at break and impact strength of the composites. Fracture morphology of the composite as well as the water absorption capacity has been monitored.